WASHINGTON - While Sacramento businesswoman Mary Ose and state Sen. Rico Oller battle it out with former California Attorney General Dan Lungren over who should be the Republican to compete for the 3rd Congressional District, a parallel battle is being played out on a larger stage.

The conservative Club for Growth, which was expected to top $125,000 in contributions to Oller's campaign by the end of last week, is in a pitched battle against the moderate Republican Main Street Partnership, which soon will open a $150,000 ad blitz for Ose.

The two organizations represent the polar extremes of the divided Republican Party, and their bitter clash over values and principles is on display in the March 2 primary contest to succeed retiring Rep. Doug Ose, Mary Ose's younger brother.

The Club for Growth already has angered the Mary Ose campaign because of ads it ran for Oller last month that she said violated federal law because they did not contain required disclaimers.

"If we are going to restore morality to government, we need to start with the way campaigns are conducted," she charged.

But the Club for Growth insisted federal laws were strictly complied with, and the club's president, Stephen Moore, denounced Mary Ose's accusations in an interview last week as her "bout with mad Dean disease," a reference to Democratic presidential contender Howard Dean.

This is hardly the biggest battlefield between the two ideological opposites this year.

Characteristic of its scorn for Republicans who aren't conservative enough, the Club for Growth will spend as much as $1.75 million on behalf of Rep. Patrick Toomey in an effort to unseat Pennsylvania Republican Sen. Arlen Specter, whom it regards as too liberal to hold office under the GOP mantle.

Two years ago, the club targeted moderate Republican Rep. Sherwood Boehlert of New York for defeat in another primary. Boehlert squeaked by, but later complained about a blizzard of last-minute club mailings and money that caught his campaign totally off guard.

That's not likely to happen this year in either Pennsylvania or Sacramento, said Sarah Chamberlain Resnick, executive director of the Republican Main Street Partnership, whose political arm is called the Main Street Fund.

"We always defend our own against the Club for Growth," she said.

"Enemies is a strong word for it, but we certainly have done battle many times in the past," she said. "They've never beaten us, and I don't intend to let them beat us here (in Sacramento), either."

Doug Ose is a member of the partnership's policy board but has no connection to its political activities, Resnick said. Both the congressman and his sister's campaign are unaware of the independent ads the group will run on her behalf, she said.

The Club for Growth is equally determined to see Oller in Congress.

"Rico is one of our top-priority candidates," Moore said. "We think that he has that star power to him where he could some day run for governor or the Senate, or something like that."

Unmentioned in the 3rd District skirmish between the two groups is the third major candidate in the Republican primary, Lungren. Though there has been no public polling that reveals a trend in the contest, the partnership and the club are circling each other as if no one else is in the race.

"In my opinion, it's really a two-man race now between Ose and Oller," Moore said.

"I think Ose is the bigger threat because of her money," Moore said in an interview Thursday, the day after Mary Ose announced that she had pumped another $425,000 of her personal fortune into her campaign, bringing her total investment to about $800,000 so far.

Moore said the club wouldn't be mortified if Lungren, who represented Long Beach in the House for 10 years before his 1990 election as attorney general and who calls himself a Ronald Reagan conservative, slipped ahead and won the primary.

"But Lungren is yesterday and Oller is tomorrow," the club president said. "Lungren is the past in our party, and people still have a bad taste in their mouths from Lungren's gubernatorial race. ...

"If you look at a profile of the kind of people we endorse, we like young hard chargers who we think have a bright political future. Lungren is at the twilight of his political career."

The goal of the club is to elect anti-tax, pro-trade Republicans who believe in smaller government and less regulation, Moore said.

Once such candidates are identified, the club sends messages to its 15,000 members around the country recommending their election. Club members then send in campaign contributions, typically in $50 or $100 increments but sometimes for $1,000 or $2,000. These checks are then sent on to the candidate with the club serving as the conduit.

Moore said this strategy gets around the $5,000-per-election contribution limits that apply to political action committees, thus permitting the club to have a much bigger influence.

For Oller, the club's endorsement is responsible for at least 10 percent of his total contributions - a figure that's much higher if Oller's personal contribution of $250,000 to his $1 million campaign isn't counted.

Resnick thinks the goal of the club couldn't be more destructive to the Republican Party. She argues it goes well beyond the fiscal issues such as reducing taxes, on which Oller, Lungren and Mary Ose hold virtually identical positions.

Resnick pointed to the Pennsylvania Senate battle that is splitting Republicans in a swing state that could be crucial to the re-election of President Bush in November.

Specter regards the club's attack as the work of the extreme right whose mission is to threaten and intimidate Republicans who don't share their narrow views.

"When the Club for Growth says they want Arlen Specter's scalp on the wall - those are their exact words - so other senators will behave, that pretty much is a clarion call to fight for a big tent," Specter declared in a January interview with the Philadelphia Inquirer.

Resnick said that widening the tent is essential theology for the Republican Main Street Partnership, which backed Arnold Schwarzenegger in California's fall gubernatorial recall election.

"We are the largest moderate Republican organization in the country," she said. "Our political mission is to expand the umbrella of the Republican Party."

Resnick said the 3rd District primary reflects the essence of what the larger internal battle in the Republican Party is all about.

"Moore thinks Rico Oller is the face of the Republican Party," she said.

"We think Mary Ose is. She's maybe a little green. But we think a moderate willing to compromise, willing to work together to compromise, is better for the Republican Party and better for the country as a whole."